How the Welsh electoral system works

Monday 5 February 2007 11.25 EST
First published on Monday 5 February 2007 11.25 EST

The assembly is made up of 60 members. Forty are elected using the first-past-the-post system in constituencies identical to Wales's Westminster seats.

A further 20 are elected from five electoral regions - such as "north Wales", "south Wales central", etc. - with four drawn from each region.

These additional assembly members are chosen from party lists, with numbers decided according to a complicated PR system designed to reward parties that get a large spread of votes which is not concentrated enough to win constituencies outright.

Voters therefore have two votes, which can be cast for different parties, but need not be.

In the last election, for example, Labour won only in constituencies and secured no top-up seats, whereas the Tories only won in one constituency (Monmouth).

Their strength in the assembly is almost entirely dependent on the 10 AMs that the PR system gave them.

A total of 31 seats are needed to form a majority in the assembly, although since an assembly member from the second-biggest party becomes the speaker, and usually does not vote, 30 seats are enough to form a working majority.

Labour won 30 seats in 2003, but no party is likely to do so this time.

Unlike Westminster, elections to the Welsh assembly are fixed for every four years - although under the provisions of the Government of Wales Act 2006, which comes into force after May, an extraordinary election can be called if two-thirds of the assembly vote for it, or if the assembly cannot decide on a first minister.